The last new UAV we talked about for the Navy was back in December of 2010 when the X-47B demonstrator first appeared. That unmanned X-47B demonstrator has hit a new milestone that is very important. The demonstrator has made its first flight with its landing gear retracted in cruise configuration.

During the flight, which took place from Edwards Air Force Base, the precision navigation hardware and software was validated. This is the software and hardware that will allow the fighter to land on the deck of a moving ship.

"Last week's flight gave us our first clean look at the aerodynamic cruise performance of the X-47B air system…and it is proving out all of our predictions," said Janis Pamiljans, vice president and Navy UCAS program manager for Northrop Grumman's Aerospace Systems sector. "Reaching this critical test point demonstrates the growing maturity of the air system, and its readiness to move to the next phase of flight testing."

The flight was part of the expanded envelop of the first two X-47B aircraft that were built by Northrop Grumman for the Navy Unmanned Combat Air System Carrier Demonstration program. The X-47B is set to start carrier testing in 2012.

The design of the X-47B allows for attack missions with low observability, and the aircraft uses no tail, looking like a combination of the F-117 Nighthawk and the B-2 Spirit.

Just to piggyback on your explanation:The U.S. military uses an MDS (Mission, Design, Series) designation for aircraft. So X-47B equals:M=Mission (X-experimental)D=Design Number (47th design)S=Series (B-second variant)Note: There are ALWAYS exceptions to the rules, and aircraft can have more than one mission (MC-130H, KC-10, SR-71, etc).The Design numbers reset to 1 a few years ago, so we could see repeats of numbers from previous aircraft (ala another B-17), but it's unlikely.Haven't seen an MDS go beyond the "Z"series, though, so no idea what would happen there.

As a note, SR-71's designation having two letters doesn't refer to dual roles. SR-71s were strict reconnaissance craft. SR stands for Strategic Reconnaissance. It was originally supposed to have the designation of RS-71 (Recon. Mission, Spaceplane airframe), but there was a general that liked Strategic Recon. better, and lobbied to have the name changed. The 71 was because it followed the Original Bomber numbering system (B-70 was the design prior in that group).